This invention relates generally to electrical connectors and more particularly to patchcord connectors for terminating one or more insulated conductors and electrically interconnecting the conductors to a terminal board or other electrical component. In one important embodiment, the present invention relates to an improved patchcord connector for multi-conductor electrical cables having means for independently terminating individual conductors and also including separate strain relief means for each conductor and a strain relief for the entire cable.
In data processing and in communication systems, and particularly in telephone communication systems, it is necessary to be able to rapidly connect and disconnect particular lines with other selected lines or series of lines through a terminal or patch board. Patchcords designed for this purpose are used, for example, in telephone exchanges and telephone central offices. They are also used in office and apartment buildings where large numbers of incoming lines must be interconnected with inside telephone lines.
These patchcords are conveniently terminated at one or both ends with connectors which must exhibit a high degree of reliability, particularly in view of the numerous mating cycles encountered in their use. Accordingly, patchcord connectors should be ruggedly constructed and designed with adequate strain relief to prevent disengagement of the conductors should the patchcord be pulled or tugged during mating of the connector.
In addition to being reliable, it is also important that patchcord connectors be simple in construction and easy to assemble in the field. Prior patchcord connector designs have attempted to meet these field assembly requirements by utilizing such refinements as two piece assembly, partial pre-assembly, and insulation piercing contacts. It has been found, however, that in spite of the putative advantages inherent in each of these prior refinements, in practice they have suffered significant shortcomings.
For example, in two-piece connectors it has been found to be awkward and time-consuming to hold conductors in place while the two connector pieces are assembled. Even where means are provided for gripping the individual conductors within one of the connector parts prior to assembly, the manipulation of the two connector parts nevertheless presents unnecessary complication in the field.
Particularly pre-assembled patchcord connectors, on the other hand, have in the past been complex to make and to use. These prior connectors generally have required the use of special tools for terminating the conductors within the connector.
Although the introduction of insulation piercing contacts in general is a most important development since it eliminates the need for soldering, the use of these contacts in patchcord connectors has presented certain drawbacks. These contacts generally require very precise positioning of contacts and corresponding conductors prior to termination; the application of termination force, similarly, must be very carefully and precisely made. This sort of precision is difficult to achieve in the field. Contact distortion problems arise in the most common field terminable connector designs where the insulated conductor is held in place and the contact moved against it. Contacts designed to be moved during termination in this way must be specially reinforced to prevent such distortion.
When used with multiple conductors, prior patchcord connectors have generally required that all conductors be terminated at one time. This presents handling difficulties in the field. Furthermore, where each conductor cannot be separately handled and terminated, uncertainty arises as to whether all of the conductors have been properly terminated. In addition, in these prior bulk termination connectors, it is not possible to add, or to remove, a single conductor after initial assembly and termination is complete.
Finally, prior patchcord connectors have often provided inadequate strain relief, especially in the case of multiple conductor connectors. Prior connectors have failed to offer separate strain relief for the individual conductors and for the multiple conductor cable itself.
It is therefore the object of the present invention to provide an improved patchcord connector which overcomes the above-mentioned deficiencies of the prior art. As described in further detail below, the patchcord connectors described herein are of simple, rugged construction and are readily pre-assembled for later use in the field. The connectors are each capable of independently terminating a number of separate insulated conductors, and they include separate strain relief means for each individual conductor as well as for the multi-conductor patchcord itself.